Vibration-Based Damage Detection of Steel Pipeline Systems

Abstract

This chapter is devoted to a numerical study of the vibration-based damage detection (VBDD) techniques of steel pipeline systems. VBDD techniques are thought to be worldwide non-destructive evaluation (NDE) techniques. VBDD techniques are based on detecting damage by using changes in the dynamic features of a structure that were a result of the defect VBDD techniques have specific advantages over local NDE techniques. For example, VBDD techniques shortly estimate the state of the whole structure. Moreover, they have not restrictions to accessible components. Well-controlled numerical experiments of finite element model of steel pipeline system demonstrated that it is possible to reliably detect damage at different locations, as well as to locate VBDD techniques, applying relatively few sensors (strain gauges or accelerometers) and taking into account changes that happen to the essential vibration mode. Determination of eigenfrequencies and mode shapes for mechanical systems is one of the most important tasks, which allow receiving integrated information about the structure state. The aim of this chapter is to analyze the results of the vibration method for determining the degree of damage in pipeline system, and development of a software module for the damage localization in structures. In the result of this work, it was found, if mode shapes were well defined with a large number of measurement points, then the damage location could be determined with great accuracy, using any of the four VBDD techniques investigated. During this research, it was established that the probability of successful damage localization depends on the damage severity, the trials number. The latter is applied for getting the average mode shape, the distance between the support and the damage, the disposition of damage in respect to the nearest sensor, and the measurement errors magnitude. The method is offered for calculating the probability of successful detection and localization of the damage. It is based on the measured mode shapes repeatability. As a conclusion, this research results demonstrate that VBDD techniques are a perspective tool to monitor structural health of pipeline systems. However, while these methods are capable to detect effectively small-size defect under well-controlled conditions, a significant amount of challenging work should be performed before the methods can be applied to real structures.